I have set the main function to:

function main()
{ var i; var j;
vec_set(sky_color,vector(0,0,0));
level_load(NULL);
video_window(NULL,NULL,0,"Laser demo");
vec_set(camera.x,vector(-250,0,50));
vec_set(camera.pan,vector(0,-15,0));
while (1){
if (mouse_left == 1){
if(proc_status(tracer_right) < 5){gun1=ent_create(NULL,vector(-100,-170,-80),tracer_right);i++;}
if(proc_status(tracer_left) < 5){gun2=ent_create(NULL,vector(-100,170,-80),tracer_left);j++;}
}
if((proc_status(tracer_right) == 0) && (i>0)){ptr_remove(gun1);i--;}
if((proc_status(tracer_left) == 0) && (j>0)){ptr_remove(gun2);j--;}
wait(1);
}
}

but still though very rarely I get that error.

I'm sorry I can't help you with your problem but I think the people helping you with this would
appreciate it if you'll write your code with the code tags for easier reading / understanding:

[code] (your code here) [/code]

From the first code sample you posted just place an "ptr_remove(me);" in your tracer_xxxxx functions just after the while loop. That should do the trick.

I am a bit confused on the vectors. If I tilt or pan the camera the 2 beam starting points will need to shift as well. What formula do I need to use so that the starting points are always on the left and right of the camera even when I tilt or pan?

You need to use vec_rotate, f.i. as follows:

VECTOR temp;
vec_set(temp,vector(16,-8,0)); // in front of the camera and 8 quants to the right side
vec_rotate(temp,camera.pan);
vec_add(temp,camera.x);

Is it possible to use the c_move command with beam particles?

What I need is that the laser beam particle always moves from its start position at vector(camera.x,camera.y-400,camera.z) or vector(camera.x,camera.y+400,camera.z) to the vector(camera.x+400, camera.y, camera.z-30)

c_move can do that but can it be used with beam particles?

Also the manual in the effect command mentions a Beam Length but I cannot find any description how to use it. Can someone shed some light on this?

You can't use "c_move" with particles (you need collusions, or don't you just know how to move them?).

No I do not need collisions, I just do not know how to handle the vector mathematics.

If what I wrote right here, is just like a Chinese language for you, go learn from workshops, AUM and manual!

In which function should this go the tracer_XXXXX or the p_trace function?